to make specified recommendations or comments (as defined in section 9) that, in the coroner's opinion, may, if drawn to public attention, reduce the chances of the occurrence of other deaths in circumstances similar to those in which the death occurred;

Persons appointed as Coroner "must have held a practising certificate as a barrister or solicitor for at least 5 years."

I'm sure that these are all smart and diligent people. I'm also sure that there is no required training in cost-benefit analysis in a legal degree.

The problem seems to be in the Act. Pretty much anything that could reduce the chances of particular forms of death can be recommended; there's no consideration anywhere of costs. It's fine to say that that's Parliament's job. But Coronorial recommendations carry some weight - people take them as being something more than "This is something that could save lives, but I have no clue whether it's worth it because I have zero training in policy assessment and cost-benefit analysis, so somebody else better figure out whether we'd be wasting a whole ton of resources in enacting it; moreover, the Act specifically asks me to just name any darned thing that might help even if it would cost a trillion dollars and save a life every fifty years."

I'd be willing to bet that a reasonable proportion of the above recommendations would fail any serious cost-benefit analysis. Mandatory high vis clothing for cyclists, licenses for nail guns, and mandatory skateboard helmets all seem exceptionally unlikely to pass any kind of "is this a reasonable policy" test.

This economist recommends that either Coroners get training in cost-benefit analysis, or start noting the limitations of their recommendations.

Coroner recommends instant fines for people who get too close to a glacier without authorisation: http://www.windy.gen.nz/index.php/archives/551

Coroner recommends "peer review" for decisions by search and rescue experts: http://www.stuff.co.nz/3429667. This one in particular would probably cause more deaths than it saved, with delays in decision making, and also from a culture of blame that would encourage those in charge to send volunteers into dangerous situations when not necessary.